// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * (c) 1998    Grant R. Guenther <grant@torque.net>
 *
 * friq.c is a low-level protocol driver for the Freecom "IQ"
 * parallel port IDE adapter.   Early versions of this adapter
 * use the 'frpw' protocol.
 *
 * Freecom uses this adapter in a battery powered external
 * CD-ROM drive.  It is also used in LS-120 drives by
 * Maxell and Panasonic, and other devices.
 *
 * The battery powered drive requires software support to
 * control the power to the drive.  This module enables the
 * drive power when the high level driver (pcd) is loaded
 * and disables it when the module is unloaded.  Note, if
 * the friq module is built in to the kernel, the power
 * will never be switched off, so other means should be
 * used to conserve battery power.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <asm/io.h>
#include "pata_parport.h"

#define CMD(x)							\
	do {							\
		w2(4); w0(0xff); w0(0xff); w0(0x73); w0(0x73);	\
		w0(0xc9); w0(0xc9); w0(0x26);			\
		w0(0x26); w0(x); w0(x);				\
	} while (0)

#define j44(l, h)	(((l >> 4) & 0x0f) | (h & 0xf0))

/*
 * cont = 0 - access the IDE register file
 * cont = 1 - access the IDE command set
 */
static int cont_map[2] = { 0x08, 0x10 };

static int friq_read_regr(struct pi_adapter *pi, int cont, int regr)
{
	int h, l, r;

	r = regr + cont_map[cont];

	CMD(r);
	w2(6); l = r1();
	w2(4); h = r1();
	w2(4);

	return j44(l, h);
}

static void friq_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
{
	int r = regr + cont_map[cont];

	CMD(r);
	w0(val);
	w2(5); w2(7); w2(5); w2(4);
}

static void friq_read_block_int(struct pi_adapter *pi, char *buf, int count, int regr)
{
	int h, l, k, ph;

	switch (pi->mode) {
	case 0:
		CMD(regr);
		for (k = 0; k < count; k++) {
			w2(6); l = r1();
			w2(4); h = r1();
			buf[k] = j44(l, h);
		}
		w2(4);
		break;
	case 1:
		ph = 2;
		CMD(regr + 0xc0);
		w0(0xff);
		for (k = 0; k < count; k++) {
			w2(0xa4 + ph);
			buf[k] = r0();
			ph = 2 - ph;
		}
		w2(0xac); w2(0xa4); w2(4);
		break;
	case 2:
		CMD(regr + 0x80);
		for (k = 0; k < count - 2; k++)
			buf[k] = r4();
		w2(0xac); w2(0xa4);
		buf[count - 2] = r4();
		buf[count - 1] = r4();
		w2(4);
		break;
	case 3:
		CMD(regr + 0x80);
		for (k = 0; k < count / 2 - 1; k++)
			((u16 *)buf)[k] = r4w();
		w2(0xac); w2(0xa4);
		buf[count - 2] = r4();
		buf[count - 1] = r4();
		w2(4);
		break;
	case 4:
		CMD(regr + 0x80);
		for (k = 0; k < count / 4 - 1; k++)
			((u32 *)buf)[k] = r4l();
		buf[count - 4] = r4();
		buf[count - 3] = r4();
		w2(0xac); w2(0xa4);
		buf[count - 2] = r4();
		buf[count - 1] = r4();
		w2(4);
		break;
	}
}

static void friq_read_block(struct pi_adapter *pi, char *buf, int count)
{
	friq_read_block_int(pi, buf, count, 0x08);
}

static void friq_write_block(struct pi_adapter *pi, char *buf, int count)
{
	int k;

	switch (pi->mode) {
	case 0:
	case 1:
		CMD(8); w2(5);
		for (k = 0; k < count; k++) {
			w0(buf[k]);
			w2(7); w2(5);
		}
		w2(4);
		break;
	case 2:
		CMD(0xc8); w2(5);
		for (k = 0; k < count; k++)
			w4(buf[k]);
		w2(4);
		break;
	case 3:
		CMD(0xc8); w2(5);
		for (k = 0; k < count / 2; k++)
			w4w(((u16 *)buf)[k]);
		w2(4);
		break;
	case 4:
		CMD(0xc8); w2(5);
		for (k = 0; k < count / 4; k++)
			w4l(((u32 *)buf)[k]);
		w2(4);
		break;
}
}

static void friq_connect(struct pi_adapter *pi)
{
	pi->saved_r0 = r0();
	pi->saved_r2 = r2();
	w2(4);
}

static void friq_disconnect(struct pi_adapter *pi)
{
	CMD(0x20);
	w0(pi->saved_r0);
	w2(pi->saved_r2);
}

static int friq_test_proto(struct pi_adapter *pi)
{
	int j, k, r;
	int e[2] = { 0, 0 };
	char scratch[512];

	pi->saved_r0 = r0();
	w0(0xff); udelay(20); CMD(0x3d); /* turn the power on */
	udelay(500);
	w0(pi->saved_r0);

	friq_connect(pi);
	for (j = 0; j < 2; j++) {
		friq_write_regr(pi, 0, 6, 0xa0 + j * 0x10);
		for (k = 0; k < 256; k++) {
			friq_write_regr(pi, 0, 2, k ^ 0xaa);
			friq_write_regr(pi, 0, 3, k ^ 0x55);
			if (friq_read_regr(pi, 0, 2) != (k ^ 0xaa))
				e[j]++;
		}
	}
	friq_disconnect(pi);

	friq_connect(pi);
	friq_read_block_int(pi, scratch, 512, 0x10);
	r = 0;
	for (k = 0; k < 128; k++) {
		if (scratch[k] != k)
			r++;
	}
	friq_disconnect(pi);

	dev_dbg(&pi->dev,
		"friq: port 0x%x, mode %d, test=(%d,%d,%d)\n",
		pi->port, pi->mode, e[0], e[1], r);

	return r || (e[0] && e[1]);
}

static void friq_log_adapter(struct pi_adapter *pi)
{
	char *mode_string[6] = { "4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32"};

	dev_info(&pi->dev,
		 "Freecom IQ ASIC-2 adapter at 0x%x, mode %d (%s), delay %d\n",
		 pi->port, pi->mode, mode_string[pi->mode], pi->delay);

	pi->private = 1;
	friq_connect(pi);
	CMD(0x9e);  		/* disable sleep timer */
	friq_disconnect(pi);
}

static void friq_release_proto(struct pi_adapter *pi)
{
	if (pi->private) {		/* turn off the power */
		friq_connect(pi);
		CMD(0x1d); CMD(0x1e);
		friq_disconnect(pi);
		pi->private = 0;
	}
}

static struct pi_protocol friq = {
	.owner		= THIS_MODULE,
	.name		= "friq",
	.max_mode	= 5,
	.epp_first	= 2,
	.default_delay	= 1,
	.max_units	= 1,
	.write_regr	= friq_write_regr,
	.read_regr	= friq_read_regr,
	.write_block	= friq_write_block,
	.read_block	= friq_read_block,
	.connect	= friq_connect,
	.disconnect	= friq_disconnect,
	.test_proto	= friq_test_proto,
	.log_adapter	= friq_log_adapter,
	.release_proto	= friq_release_proto,
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Grant R. Guenther <grant@torque.net>");
MODULE_DESCRIPTION("Freecom IQ parallel port IDE adapter protocol driver");
module_pata_parport_driver(friq);